Louvre shutters and doors are generally manufactured with a rectangular frame fitting within the space of the window or door to be covered. A number of horizontal louvre slats or blades extend from one side frame to the other. Usually they are linked together by some means such as a pull rod, so that all of the slats can be pivoted open or closed in unison.
Other forms of pull rod pivoting mechanisms are known.
U.S. Pat. No. 5,469,658 granted Nov. 28, 1995 entitled LOUVRE SHUTTER DEVICE WITH VARIABLE SLATS, Inventor M. Digianni et al. illustrates an improved form of shutter fabricated of extruded plastic material. The shutter shown in that patent provides for opening and closing of the shutter slats by means of rack and pinion gears. The shutter slats are located spaced apart along the two side frames, and the spacing is variable, from one shutter assembly to another, depending upon the measurements of the door or window opening, to which it will be fitted.
This system overcame the problem with prior art shutters and shutter doors, in which the only adjustment for height was to simply cut off part of the bottom or top frame of the shutter.
The manufacture of the shutters shown in the aforesaid U.S. patent, with slats located on different centres from one shutter to another, required the drilling of holes in the two side frames, with the holes being drilled precisely at the desired centres for the slat spacing of that particular shutter. If that type of shutter were to be used with a pull rod, then the pull rod would also have to be drilled with holes at the precise spacing of the slats, so that the slats could be connected to the pull rod.
Drilling these holes at precisely predetermined centres for both side frames and for the pull rod, and varying the spacing of the centres from one shutter assembly to another, required the use of highly skilled labour. Eventually a machine was developed for carrying out this system. However, the machine was capable only of drilling two side frames, and one pull rod, at a time. As a result, the productivity of the machine was relatively low, leading to unnecessarily high costs in the production of such shutters.
It will of course be appreciated that sales persons will be receiving orders for window shutters or door shutters having different height dimensions, requiring the spacing of the slat holes and pull rod holes to be varied, and in the old machine it was necessary to reset the machine for each order to ensure that the holes were drilled on the correct centres.
Larger holes are required for carrying the rotational hubs of the slats themselves and smaller holes are required in the pull rod for carrying the pieces connecting the pull rod to the slats. As a result, the drilling loads on the machine had to be able to accommodate both the larger holes and the smaller holes.
In order to do this, the older machine had a central longitudinal carriage with a cross bar mounted on the carriage. Two drills were mounted on the cross bar on one side of the carriage and one drill was mounted on the cross bar on the other side of the carriage. Movement mechanism was provided for moving the cross bar along the central carriage.
Clamps were provided for clamping the work pieces, ie. the side frames and the pull bar, in position underneath the appropriate drills for drilling.
Clearly, it was desirable to improve the output of such a machine and at the same time provide for computer controlling of the drilling operations and the clamping operations, and the location of the various work pieces relative to the drill heads, so as to produce components for two shutters simultaneously, thereby doubling the production of the machine, and improving its control of variable spacing.
It is further desirable to provide a means for controlling the depth of the drill holes, so that in some cases drill holes can be drilled in one side only of each component and in other cases drill holes can be drilled through both sides of some components, depending upon the design and construction of the particular shutter being constructed.
While the invention is described in association with the drilling of components for shutters, it will be appreciated that the invention is of much broader application, and is not confined exclusively to the drilling of shutter components.